In recent years, in working fields where printing operations are conducted by image forming apparatuses, the image forming apparatuses, combined with plural sheet supplying trays, are used so that the printing operations are conducted on various sizes and types of sheets. Accordingly, the operator must conduct various adjustments on the image forming apparatus, and supply the recording sheets to the apparatus. Further, since the operator sets plural printing adjustments on the apparatus, and applies the plural types of recording sheets to the apparatus, the operator can register a large number of printing sets.
In order to effectively conduct the printing operation according to the plan, before the operator starts the printing job, the operator is required to know which sheet supplying tray is to be used for the printing job, and the operator is also required to adjust the sheet supplying tray, and replenish the recording sheets.
In order to guide sheet supplying jobs to the operator, Unexamined Japanese Patent Application Publication 2004-348,713 discloses a printing system using a display unit on which a schedule for each printing job is displayed. The types of recording sheets accommodated in the sheet supplying trays are displayed on the vertical axis of a screen of the display unit, while working times and amount of recording sheets to be used are displayed on the horizontal axis of the screen of the display unit, whereby the working schedule can be displayed in a graph form.